The Hudson Valley between northern Westchester county in the south and Albany to the north is an area called "the Great Estates Region" where many of the American elite built their mansions in the nineteenth or early twentieth century.
Less than 100 miles up the The Hudson River from New York City it had beautiful views of the river, the Catskill Mountains and glorious fall foliage.Source:squidoo.com

History:

1609 - Henry Hudson, an Englishman sailing for the Dutch East India Company, sailed the Half Moon up the North River (later renamed for him) in search of the Northwest Passage.

1614 - Fort Nassau built at present-day Albany the site of an earlier French fort dated to 1540.

1623 - Fort Orange was built to replace Fort Nassau as a fur-trading post.

1624 - The Dutch West India Company was sending people to America and settlement of the Hudson River Valley was underway.

late 1600's - All the Native American tribes living near the Hudson had been decimated by small pox, which the settlers brought with them and by wars with the Dutch. See: Native American Tribes of the Hudson River

1683 - Land in todays Columbia County is purchased from the Mohegan Indians.

1686 - Robert Livingston receives grants of large tracts of land in what is now the southern part of Columbia County.
The Schuyler Patent issued to Peter Schuyler included present day Red Hook.
See patent map.

1697 - The "Great Nine Partners Patent" granted land which covered the area between the Hudson River in the west and the border of Connecticut in the East to a group of nine businessmen from New York City by the English Crown. It included the Springwood "water lot" at what is today Hyde Park.
The Rhinebeck patent

Mid 1800's - The Hudson River School was a mid-19th century American art movement embodied by a group of landscape painters whose aesthetic vision was influenced by romanticism. The paintings for which the movement is named depict the Hudson River Valley and the surrounding area, including the Catskill, Adirondack, and the White Mountains. Artists included Thomas Cole (1801-1848), Frederic Edwin Church (1826-1900), John Frederick Kensett (1816-1872), and Sanford Robinson Gifford (1823-1880).

1825 - The Erie Canal is completed connecting Lake Erie to the Hudson just above Albany to facilitate transport of goods between the Great Lakes and New York City.

1876 - 1917 - American Gilded Age also known as the American Renaissance, this period in American history was marked by America's rapid economic growth and emergence as a world power. America's financial and industrial leaders built estates in the Hudson Valley.

The Mills and Vanderbilt families were at the center of New York society life at the turn of the last century.

Geology:
One billion years ago, in the Precambrian period, the Grenville orogeny (the name for a mountain-building event) was a major force in this area. This event turned the rocks into the gneisses (sedimentary rock that has been subjected to great heat and pressure and has metamorphosed into a very hard rock) and granites that we see today, in the Hudson Highlands. The only other New York sites for this ancient rock, which has successfully resisted erosion, are in the Adirondacks.
The Taconic orogeny, 450 million years ago created rock that is brittle, mostly sedimentary shale.

Two more orogenies, the Acadian, 410 to 380 million years ago, and the Alleghanian, 320-280 million years ago continued to shape the building of the continent.

Between 300 million and 200 million years ago, a supercontinent began splitting apart. It was during this period of land splitting apart, in the Mesozoic, that the Palisades were formed and it left a gap the Hudson would eventually fill.

26,000 - 13,000 years ago the Hudson Fjord is created by the Wisconsin Stage of the last Glacial age.

The Shawangunk ridge area in the southern Catskills contains one of the largest known exposed fault system in the United States.
Shawangunk Conglomerate, a hard, silica-cemented conglomerate of white quartz pebbles and sandstone. It was exposed by uplifting during the Permian (about 270 million years ago).

The tide in the Hudson River is the continuation of the tide-wave, which comes up from the ocean through New York Bay, and is carried by its own momentum one hundred and sixty miles, growing, of course, constantly smaller, until it is finally stopped by the dam at Troy.